The invention relates to a process for metallizing a solid body, in particular, a vitreous, glass-like surface containing a silicate material.
Solid bodies are metallized to change, improve and/or broaden their functional characteristics, e.g. their electrical conductivity, corrosion resistance, wear resistance and/or also their decorative characteristics. Generally, the adhesive strength of such metallizations is of great significance. The adhesion of a layer may be effected, for example, by relatively weak interaction between the materials of the layer and of the substrate (so-called Van der Waals forces), by chemical bonds or by mechanical anchoring and/or a combination of such contributions.
Processes are known with which layer adhesion can be improved. For example, adhesion promoting intermediate layers may be precipitated in the form of adhesives or as vapor-deposited and/or sputtered layers. Better layer adhesion is realized by roughening the substrate, e.g. in a grinding process, and/or by swelling and roughening the surface by way of chemical etching and/or by embedding dissolvable impurities in the adhesion promoter.
These known processes are limited to certain applications and special combinations of materials. Adhesion promoters are composed of a material which is different from the substrate and from the desired coating, so that incompatible characteristics occur or the desired layer characteristics must be restricted. For example, adhesion promoters in adhesive layers reduce the thermal stressability of the coated bodies. Inorganic adhesion promoters require uneconomical coating processes. Roughened substrate surfaces are annoying wherever very fine metallization structures are required or where there is a demand for special optical characteristics, such as reflection.